Hitherto, there has been known a solenoid valve control device in which a switching element and a drive coil for a solenoid valve are connected in series to an output unit which outputs a direct-current voltage after performing a full-wave rectification on an alternating-current voltage output from an alternating-current power source, and the solenoid valve control device is configured to control the valve-open and valve-close of the solenoid by controlling the ON and OFF of the switching element (for example, refer to Japanese Patent Laid-open No. H01-316583).
The solenoid valve control device disclosed in Patent Document 1, a relay is adopted as the switching element and the drive coil for the solenoid valve is connected in parallel to a light-emitting diode in a photocoupler; and a disposition deficiency or the like of a contact to the relay is detected by inputting pulse signals based on the ON and OFF of a light-receiving transistor in the light-emitting diode into a microcomputer.